JPH04117147U - variable compression ratio engine - Google Patents

Abstract

(57) [Summary] [Objective] The present invention is to provide a variable compression ratio engine that can increase combustion speed. [Structure] This variable compression ratio engine has a subchamber 2 formed in a cylinder head 3 and a main combustion chamber 1 formed in a piston 5. A compression ratio variable valve 7 is disposed in a communication hole 6 that communicates the main combustion chamber 1 and the sub-chamber 2, and a blade 10 is provided on the valve blade 16 of the compression ratio variable valve 7. It provides a strong air flow to the jet of flame and mixture to accelerate the mixing speed and combustion speed in the main combustion chamber 1, shorten the combustion period, improve output, and reduce HC, _NOx , and unburned Suppresses gas generation.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This idea is based on a variable compression ratio engine equipped with a variable compression ratio valve in the communication hole between the main combustion chamber and the auxiliary chamber. Regarding engine.

0002

[Conventional technology]

Conventionally, in internal combustion engines, a combustion engine with a valve in the communication hole between the main combustion chamber and the auxiliary combustion chamber has been used. A variable compression ratio internal combustion engine is disclosed in, for example, Japanese Utility Model Application Publication No. 57-164224. Ru. The variable compression ratio internal combustion engine connects a combustion chamber of the internal combustion engine to an auxiliary combustion chamber via a third valve. The third valve is driven by a variable valve timing mechanism, and in the low load range It remains closed and burns at a high compression ratio, and the cam-based valve mechanism is activated in high load ranges. The engine is opened from the middle of the compression process to the latter half of the exhaust process, and combustion is performed at a low compression ratio. Ru.

0003 In addition, Japanese Patent Application No. 1-256418 filed by the present applicant describes a combustion chamber variable engine. The engine is disclosed. The combustion chamber variable engine is installed at the head of the main combustion chamber. a sub-combustion chamber that communicates with the main combustion chamber, and a communication port between the sub-combustion chamber and the main combustion chamber. A valve driving means for driving the valve to be closed, and a valve driving means for driving the valve to be closed, and a valve driving means for driving the valve to close, and a valve driving means for driving the valve to close, and a Fuel injection means for switching fuel injection, and when the engine load is above a predetermined top surface. The valve is opened to communicate the auxiliary combustion chamber with the main combustion chamber, and the fuel injector is opened. and a combustion chamber changing means for changing fuel injection from the main combustion chamber to the auxiliary combustion chamber depending on the stage. It is something.

0004 In addition, Japanese Patent Application No. 1-182456 filed by the present applicant describes the main combustion chamber and the sub-combustion chamber. Equipped with an on-off valve in the communication hole with the combustion chamber, the on-off valve can be turned on when the engine load is light. It is maintained in the closed state to increase the compression ratio, and the opening/closing bar is closed when the engine load is large. A variable compression ratio engine that maintains the valve open and reduces the compression ratio. Disclosed.

[0005] Regarding internal combustion engine intake and exhaust mechanisms, for example, Japanese Utility Model Application Publication No. 49-53113 There are some things disclosed in the report. The internal combustion engine intake and exhaust mechanism has multiple intake and exhaust ports. The spiral protrusions are arranged in parallel, and the roots of the valve heads of the intake and exhaust valves are also provided with the same spiral protrusions. A plurality of spiral protrusions are arranged in parallel to accommodate the spiral protrusions.

[0006]

[Problem that the idea aims to solve]

As mentioned above, the variable compression ratio engine forms a subchamber in the cylinder head, and the subchamber is formed in the cylinder head. The chamber is communicated with the main combustion chamber through a communication hole, and a control valve is disposed in the communication hole. The structure is structured as follows. In this variable compression ratio engine, when starting, idling At low speeds and low loads, the control valve closes the communication hole to open the main combustion chamber. During high-speed and high-load conditions, the communication hole is opened and the main combustion is carried out at a high compression ratio. Combustion is performed at a low compression ratio in the chamber and subchamber. However, such a compression ratio is In a variable engine, the compression ratio is controlled by a control valve placed in the communication hole. Therefore, the pre-chamber cannot be configured as a swirl chamber type combustion chamber. Therefore, when combustion is performed in the main combustion chamber and the pre-chamber at high speed and high load, the combustion in the pre-chamber Regarding this, it is not possible to create a mixture between intake air and fuel due to swirl, and premix combustion is not possible. Expected to worsen.

Therefore, the purpose of this invention is to solve the above-mentioned problem, and by providing a variable compression ratio valve in the communication hole between the main combustion chamber and the auxiliary chamber, the compression ratio can be adjusted when the engine speed and engine load are low. The communication hole is closed with a variable valve and combustion is performed at a high compression ratio only in the main combustion chamber, and especially at high speeds and high loads, the communication hole is opened and combustion is performed at a low compression ratio between the main combustion chamber and the auxiliary chamber. At this time, the valve of the variable compression ratio valve has blades extending from the bottom to the valve stem, and the blades guide the intake air flowing from the cylinder into the subchamber to promote air flow within the subchamber. The blades guide and promote the air flow of the jet of flame and mixture from the auxiliary chamber to the main combustion chamber. An object of the present invention is to provide a variable compression ratio engine that can promote secondary mixing in the engine, significantly shorten the combustion speed, ensure good combustion, and prevent the generation of _NOx , HC, unburned gas, etc.

[0008]

[Means to solve the problem]

In order to achieve the above object, this invention is constructed as follows. That is, , this invention consists of a sub-chamber formed in the cylinder head, and a first nozzle hole opening in the sub-chamber. Fuel nozzle, main combustion chamber formed on the piston head side, nozzle hole for the main combustion chamber a second fuel nozzle that opens a second fuel nozzle, and a communication hole that communicates the auxiliary chamber with the main combustion chamber by electromagnetic force. A variable compression ratio valve that opens and closes at A blade formed of control opening and closing of the variable compression ratio valve in response to a detection signal of the first fuel; a controller for controlling fuel injection between the nozzle and the second fuel nozzle; Regarding a variable reduction ratio engine.

[0009] Further, in this variable compression ratio engine, the controller may control the compression ratio variable engine. The variable valve injects fuel from the first fuel nozzle with the communicating hole open, and Fuel is supplied from the second fuel nozzle with the variable compression ratio valve closing the communication hole. This controls the injection.

0010

[Effect]

The variable compression ratio engine based on this invention is constructed as described above, and has the following features. It acts like a sea urchin. That is, this variable compression ratio engine has a series equipped with a first fuel nozzle. Communication between the auxiliary chamber formed in the engine head and the main combustion chamber provided with the second fuel nozzle A variable compression ratio valve that opens and closes using electromagnetic force is installed in the hole to respond to engine operating conditions. to control the opening and closing of the variable compression ratio valve, and the first fuel nozzle and the second fuel nozzle. Since it has a controller that controls fuel injection with a fuel nozzle, for example, When the engine is partially loaded, the communication hole is closed and combustion is carried out at a high compression ratio in the pre-chamber. can be done. Also, when the engine is under high load, the compression ratio variable valve is kept open. and maintain communication between the pre-chamber and the main combustion chamber to perform combustion at a low compression ratio. be able to.

[0011] Particularly, in this variable compression ratio engine, the valve of the variable compression ratio valve is mounted on the valve stem from above. Since the blades are formed by applying the same force to the intake air flowing from the main combustion chamber side to the auxiliary chamber, The guiding action of the blades can provide a strong air flow, and the main The blade guides the combustion gas of the flame and mixture blown into the combustion chamber. The combustion gas is ejected into the main combustion chamber at high speed while giving a swirl-like motion. The combustion speed in the main combustion chamber is increased by increasing the mixing speed of combustion gas and fresh air in the main combustion chamber. speed up the combustion process and shorten the combustion period.

Generally, in the case of a conventional swirl chamber type combustion chamber, the area of the communication hole that communicates the auxiliary chamber with the main combustion chamber is about 1 to 1.5% of the top surface area of the piston, and this small jet By ejecting combustion gas and unburned gas from the holes into the main combustion chamber at high speed, the mixing speed and combustion speed in the main combustion chamber are increased. In the variable compression ratio engine according to the present invention, the communication hole that communicates the main combustion chamber and the auxiliary chamber is a communication hole for varying the compression ratio, and the passage area of the communication hole is formed to be large. Therefore, instead of narrowing down the passage area, blades are formed in the variable compression ratio valve to promote swirl in the pre-chamber.In particular, during injection after combustion, the swirl in the cylinder is already significantly attenuated. However, by forming blades on the valve of the variable compression ratio valve, it is possible to greatly increase the speed of flame and air-fuel mixture ejected from the subchamber to the main combustion chamber. The goal is to increase the combustion speed, shorten the combustion period, suppress the generation of _NOx , HC, and unburned gas, and improve engine efficiency.

[0013]

【Example】

Below, an embodiment of the variable compression ratio engine according to this invention will be explained with reference to the drawings. Ru. Figure 1 is a sectional view and diagram showing an embodiment of a variable compression ratio engine according to this invention. 2 is a sectional view taken along line A-A in FIG. As shown in the figure, this variable compression ratio engine The engine mainly consists of a cylinder head 3 fixed to a cylinder block 4, a cylinder The subchamber 2 formed in the head 3 and the inside of the cylinder 11 formed in the cylinder block 4 are The main body consists of a reciprocating piston 5 and a cavity 12 formed in the piston 5. A communication hole 6 that communicates the combustion chamber 1 and the auxiliary chamber 2 with the main combustion chamber 1 side, and a communication hole 6 are arranged in the communication hole 6. It has a variable compression ratio valve 7. The auxiliary chamber 2 formed in the cylinder head 3 is a piston The combustion chamber 1 is configured to face the main combustion chamber 1 formed in the combustion chamber 5. Therefore, the main combustion chamber 1 can also function as a relief part when the variable compression ratio valve 7 is lowered. In addition , intake and exhaust ports 19 (only one shown in the figure) are formed in the cylinder head 3, An intake/exhaust valve 18 is arranged in the intake/exhaust port 19 . In addition, the main combustion chamber 1 and the subchamber 2 may be configured with a heat insulating structure using materials such as ceramic materials and heat insulating materials. Can also be done.

In this variable compression ratio engine, the cylinder head 3 is provided with a first fuel nozzle 8 that opens a nozzle hole into the auxiliary chamber 2 , and a second fuel nozzle 8 that opens a nozzle hole into the main combustion chamber 1 . A fuel nozzle 9 is arranged. The variable compression ratio valve 7 is provided to open and close a communication hole 6 that communicates the auxiliary chamber 2 with the main combustion chamber 1, and is opened and closed by electromagnetic force by a solenoid valve drive device 15. The electromagnetic valve drive device 15 operates by, for example, passing an electric current through an electromagnetic coil to attract a magnetic member attached to the valve stem 17 of the variable compression ratio valve 7, thereby opening the communication hole 6 and stopping the energization. Accordingly, the connecting hole 6 can be configured to return to its original state using a return spring and close the communication hole 6. The variable compression ratio valve 7 is preferably made of ceramics in order to be lightweight, and has a magnetic material at the upper end of the valve stem. In particular, the variable compression ratio valve 7 is composed of a valve shank 16 and a valve stem 17, and the valve shank 16 and the valve stem 17 are chipped to form a plurality of blades 10. The blade 10 is formed in a shape that guides the gas flowing in and out of the communication hole 6 so as to generate a swirl. That is, when the intake air flows into the subchamber 2 from the cylinder 11 side, the intake air is guided by the blades 10 and generates a strong swirl flow in the subchamber 2, and this air flow causes a second flow in the subchamber 2. 1 It is uniformly mixed with the fuel spray injected from the fuel nozzle 8 for a short period of time, and the fuel is combusted in a rich manner, and the pressure is rapidly increased. Next, the combustion gases of the flame and the mixture are jetted out from the auxiliary chamber 2 into the main combustion chamber 1 at once, and at this time, the jet gas is guided by the blades 10 and flows into the main combustion chamber 1 as a strong air flow. The air is mixed with fresh air existing in the main combustion chamber 1 for a short period of time to increase the mixing speed, increase the combustion speed, shorten the combustion period, and complete combustion while suppressing the generation of HC, _NOx , and unburned gas. do.

[0015] For this variable compression ratio engine, there is a sensor that detects the engine operating status. , and a control that controls opening and closing of the variable compression ratio valve 7 in response to the detection signal of the sensor. It has a roller 20, and the controller 20 responds to the opening/closing operation of the variable compression ratio valve 7. In response, fuel injection from the first fuel nozzle 8 and the second fuel nozzle 9 is controlled. Compression ratio possible The compression ratio is low when variable valve 7 is open, and the compression ratio is low when variable valve 7 is closed. In this state, the compression ratio becomes high. The controller 20 controls the compression ratio variable valve to open the communication hole 6. In this state, fuel is injected from the first fuel nozzle 8, and the compression ratio variable valve 7 is injected through the communication hole 6. Control is performed to inject fuel from the second fuel nozzle 9 in the closed state.

[0016] In this variable compression ratio engine, the engine operating state is A rotation sensor 13 that detects the rotation speed N and a load sensor that detects the engine load L. It is 14. Engine rotation speed N is the rotation speed of the crankshaft using rotation sensor 1. It can be detected by measuring in step 3, and the engine load L can be detected by measuring the accelerator pedal. The amount of fuel to be detected or supplied to the first fuel nozzle 8 and the second fuel nozzle 9 It can be detected by measuring the flow rate with the load sensor 14.

Therefore, in this variable compression ratio engine, the opening/closing operation of the variable compression ratio valve 7 is controlled by the controller 20, and when the engine speed and engine load are low, the variable compression ratio valve 7 closes the communication hole 6. The controller closes the main combustion chamber 1 and performs combustion at a high compression ratio only in the main combustion chamber 1, and at high speeds and high loads, opens the communication hole 6 and performs combustion at a low compression ratio in the main combustion chamber 1 and the auxiliary chamber 2. Control with 20. In this variable compression ratio engine, especially when the variable compression ratio valve 7 is in an open state, the blade 10 formed from the valve stem 16 of the variable compression ratio valve 7 to the root of the valve stem 17 is inserted into the cylinder, that is, into the cylinder 11. The intake air flowing into the auxiliary chamber 2 from inside is guided, the air flow within the auxiliary chamber 2 is promoted, the mixing of fuel and air is promoted, and the fuel is ignited and burnt in a rich manner. It also promotes the flow of jet air between the flame and air-fuel mixture from the pre-chamber 2 to the main combustion chamber 1, promoting secondary mixing within the main combustion chamber 1, significantly shortening the combustion speed, and achieving good results. It is characterized by ensuring combustion and preventing the generation of _NOx , HC, unburned gas, etc.

[0018] Next, the operation of the variable compression ratio engine according to this invention will be explained. Figure 4 is here. FIG. 3 is a process flow diagram showing an example of the operation of the variable compression ratio engine devised by . en When the engine starts, the fuel injection pump, the valve mechanism of the intake and exhaust valves 18, etc. are controlled. be controlled. When starting the engine, the compression ratio variable valve 7 remains closed and the compression ratio is high. The variable compression ratio valve 7 is closed by a command from the controller 20. The chain operates to close the communication hole 6, and the controller 20 commands the second fuel nozzle 9. Controls the injection of fuel into the main combustion chamber 1, and performs combustion at a high compression ratio only in the main combustion chamber 1. cormorant. At this time, the controller 20 commands the fuel to be injected from the second fuel nozzle 9 into the main combustion chamber 1. The fuel mixed with the air in the main combustion chamber 1 is ignited and combusted. Next, load sensor -14 detects the engine load L (step 30), and the rotation sensor -13, the engine rotation speed N is detected (step 31).

The engine load L detected by the load sensor 14 and the engine rotation speed N detected by the rotation sensor 13 are input to the controller 20 . Upon receiving these input signals, the controller 20 compares and determines whether the engine load L detected by the load sensor 14 is greater than a predetermined engine load L ₀ calculated in advance (step 32). If the engine load L is larger than the predetermined engine load _L0 as determined by the controller 20, the engine is under high load and combustion is actively occurring, and the inside of the main combustion chamber 1 is under high pressure. It's at the temperature. Further, it is compared and determined whether the engine rotation speed N detected by the rotation sensor 13 is larger than a predetermined engine rotation speed N ₀ calculated in advance (step 33). If the engine speed N is larger than the predetermined engine speed _N0 as determined by the controller 20, the engine is running at high speed, combustion is actively occurring, and the inside of the main combustion chamber 1 is The temperature is high. Therefore, the solenoid valve drive device 15 is driven by a command from the controller 20 to switch the compression ratio variable valve 7 to an open state (step 34), and the combustion method is changed to a low compression ratio combustion method using the subchamber 2. Therefore, the controller 20 switches the fuel injection to the auxiliary chamber 2 side and controls the first fuel nozzle 8 to inject fuel into the auxiliary chamber 2 (step 35). The combustion chamber volume of the auxiliary chamber 2 is added to the main combustion chamber 1, and the compression ratio decreases to perform combustion at a low compression ratio (step 36).

Further, if the engine load L is smaller than the predetermined engine load L ₀ as a result of the comparative judgment of the controller 20, the engine is under partial load, and the temperature inside the main combustion chamber 1 is not so high. , there is a risk of misfire, so it is necessary to increase the compression ratio of the combustion chamber. Further, if the engine speed N detected by the rotation sensor 13 is smaller than a predetermined engine speed _N0 calculated in advance, the engine is running at low speed, and the temperature inside the main combustion chamber 1 is not so high. . Therefore, the solenoid valve drive device 15 is driven by a command from the controller 20 to switch the compression ratio variable valve 7 to the closed state, and the communicating hole 6 is closed (step 37), thereby achieving a high compression ratio that uses only the main combustion chamber 1. Change to combustion method. Therefore, the controller 20 controls the fuel injection to be switched to the main combustion chamber 1 side and injects fuel from the second fuel nozzle 9 into the main combustion chamber 1 (step 38). The combustion chamber volume becomes only that of the main combustion chamber 1, and the compression ratio increases to perform combustion at a high compression ratio (step 39).

[0021] This variable compression ratio engine repeatedly performs the combustion control described above, and is controlled by the controller 20 so that combustion is performed at the compression ratio most suitable for the engine operating condition. Therefore, this variable compression ratio engine employs a combustion method that uses the pre-chamber 2, especially at high speeds and high loads, but at that time, the blades 10 formed in the variable compression ratio valve 7 have a strong Since air flow can be provided, combustion can be performed that can suppress not only the generation of HC but also the generation of _NOx .

[0022]

[Effect of the idea]

The variable compression ratio engine according to this invention is constructed as described above and has the following effects. That is, this variable compression ratio engine includes a sub-chamber formed in the cylinder head, a first fuel nozzle that opens an injection hole in the sub-chamber, a main combustion chamber formed on the piston head side, and an injector for the main combustion chamber. A second fuel nozzle that opens a hole, a variable compression ratio valve that opens and closes a communication hole that communicates the auxiliary chamber with the main combustion chamber by electromagnetic force, and a valve of the variable compression ratio valve that extends from the valve stem. a blade, a sensor that detects the operating state of the engine, and a sensor that controls opening and closing of the variable compression ratio valve in response to a detection signal from the sensor, and controls fuel injection from the first fuel nozzle and the second fuel nozzle. When the engine is at low speed and under partial load, the auxiliary chamber is closed, so the compression ratio is increased, and the fuel injected from the second fuel nozzle into the main combustion chamber is mixed with fresh air in the main combustion chamber. is promoted, the compression ratio becomes high, the temperature rises, a good air-fuel mixture is generated, ignition occurs reliably, no ignition errors occur, smooth combustion is achieved, and HC, _NOx , and unburned gas are reduced. etc. can be prevented from occurring.

[0023]Furthermore, when the engine is at high speed and under high load, the variable compression ratio valve is maintained in an open state, so that the pre-chamber is in an open state, and the compression ratio is lowered by the volume of the pre-chamber. Combustion temperature is controlled to prevent abnormal ignition, and the intake air flowing from the main combustion chamber into the auxiliary chamber is guided by the blades to generate a strong swirl in the auxiliary chamber, and the air due to the swirl is Mixing of the flow and the fuel spray injected from the first fuel nozzle is promoted, the pressure rises rapidly, and the combustion gas of the flame and mixture is guided by the blade and is instantly transferred from the sub-chamber to the main combustion chamber. Squirts into the room. Therefore, the ejected combustion gas rapidly mixes with the fresh air in the main combustion chamber, increasing the combustion speed and completing combustion in a short period of time. In addition, the combustion gas is blown out from the auxiliary chamber to the main combustion chamber, and the combustion temperature decreases, and the fuel equivalence ratio rapidly decreases to combust, avoiding combustion in the _NOX generation combustion zone and producing _NOX . The generation is suppressed, combustion is performed smoothly, and the generation of HC, unburned gas, etc. is prevented.

[0024] Further, in this variable compression ratio engine, the controller may include the variable compression ratio engine. The valve injects fuel from the first fuel nozzle with the communication hole open, and Injecting fuel from the second fuel nozzle with the variable compression ratio valve closing the communication hole. At the same time, the variable compression ratio valve is controlled by commands from the controller. Since the opening and closing operation was performed by the electromagnetic valve drive device, the rotation of the crankshaft and can independently open and close the variable compression ratio valve under the above conditions, ensuring reliable operation. can be done.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of a variable compression ratio engine according to the present invention, with a variable compression ratio valve in a closed state.

FIG. 2 is a sectional view taken along line AA in FIG. 1;

FIG. 3 shows an example of the variable compression ratio engine of FIG. 1,
FIG. 3 is a sectional view showing a state in which the variable compression ratio valve is open.

FIG. 4 is a process flow diagram showing an example of the operation of the variable compression ratio engine of FIG. 1;

[Explanation of symbols]

1 Main combustion chamber 2 Antechamber 3 Cylinder head 5 Piston 6 Communication hole 7 Compression ratio variable valve 8 First fuel nozzle 9 Second fuel nozzle 10 blade 11 cylinder 13 Rotation sensor 14 Load sensor 15 Solenoid valve drive device 16 Bengasa 17 Valve stem 20 Controller

Claims (2)

[Scope of utility model registration request] Claim 1: A subchamber formed in a cylinder head, a first fuel nozzle that opens a nozzle hole in the subchamber, a main combustion chamber formed on the piston head side, and a nozzle hole that opens into the main combustion chamber. a second fuel nozzle, a variable compression ratio valve that opens and closes a communication hole that communicates the auxiliary chamber with the main combustion chamber by electromagnetic force, a blade formed from the valve stem of the variable compression ratio valve, and an engine. a sensor that detects an operating state of the sensor; and a controller that controls opening and closing of the variable compression ratio valve and controls fuel injection of the first fuel nozzle and the second fuel nozzle in response to a detection signal from the sensor. A variable compression ratio engine. 2. The controller injects fuel from the first fuel nozzle when the variable compression ratio valve opens the communication hole, and injects the fuel from the first fuel nozzle when the variable compression ratio valve closes the communication hole. The variable compression ratio engine according to claim 1, wherein fuel is injected from the second fuel nozzle.